Related Experiment Videos
Identification of an evolutionarily conserved, function-associated molecule on human natural killer cells
D T Harris1, L Jaso-Friedmann, R B Devlin
1Department of Microbiology and Immunology, University of Arizona, Tucson 85721.
Abstract:
Nonspecific cytotoxic cells (NCC) in teleost fish are analogous to human natural killer (NK) cells and spontaneously lyse a variety of transformed human cell lines sensitive to human NK cell lysis. Monoclonal antibodies (mAbs) made against these NK-like effector cells inhibited their lytic activity. These anti-NCC mAbs were examined with human NK cells for their effects. It was observed that these mAbs bound specifically to a small percentage of peripheral blood lymphocytes (5-15%) and to the majority (greater than 85%) of CD3- NK cells. The mAbs inhibited human NK cell lysis against a variety of transformed cell lines. Single-cell assays showed that the mAbs exerted their effects through inhibition of conjugate formation (recognition). However, the mAbs did not inhibit NK cell-mediated antibody-dependent cell-mediated cytotoxicity. Biochemical analysis of the NK cell molecule revealed that a dimeric structure was involved (distinct from antigen receptors on T cells). Thus, this molecule appears to be a candidate NK cell antigen receptor.
Insights
Monoclonal antibodies targeting fish nonspecific cytotoxic cells (NCC) also inhibit human natural killer (NK) cell activity. These antibodies block NK cell recognition, suggesting a conserved NK cell receptor molecule.
Area of Science:
- Immunology
- Comparative Biology
- Cellular Biology
Background:
- Nonspecific cytotoxic cells (NCC) in teleost fish share functional similarities with human natural killer (NK) cells.
- NCC spontaneously lyse tumor cells, analogous to human NK cell cytotoxicity.
- Previous studies generated monoclonal antibodies (mAbs) against fish NCC that inhibited their lytic function.
Purpose of the Study:
- To investigate the cross-reactivity and functional effects of anti-NCC mAbs on human NK cells.
- To identify potential conserved molecules involved in NK cell recognition across species.
- To characterize the molecular nature of the target molecule on human NK cells.
Main Methods:
- Incubation of human peripheral blood lymphocytes with anti-NCC mAbs.
- Flow cytometry analysis to determine mAb binding specificity.
- NK cell cytotoxicity assays against transformed cell lines.
- Single-cell conjugate formation assays.
- Biochemical analysis of the NK cell surface molecule.
Main Results:
- Anti-NCC mAbs specifically bound to a subset of human peripheral blood lymphocytes (5-15%) and CD3- NK cells (>85%).
- These mAbs significantly inhibited human NK cell-mediated lysis of various transformed cell lines.
- Inhibition was attributed to blocking conjugate formation (recognition), not antibody-dependent cell-mediated cytotoxicity.
- Biochemical analysis indicated the target molecule has a dimeric structure, distinct from T cell receptors.
Conclusions:
- A conserved molecule recognized by anti-NCC mAbs is present on human NK cells.
- This molecule plays a crucial role in NK cell recognition and conjugate formation.
- The identified molecule represents a potential candidate for an NK cell antigen receptor, conserved between fish and humans.